In the midst of an intense cold spell gripping a significant portion of the United States, there is an unexpected shift towards notably warmer conditions across the entire contiguous 48 states this week. The Climate Prediction Center indicates a likelihood of above-average temperatures prevailing throughout the week, with southern regions experiencing highs in the 60s and 70s. This abrupt change, termed “weather whiplash” by UCLA climate scientist Daniel Swain, is noteworthy as some areas may witness record high temperatures just a week after setting record lows.

However, this warmth is accompanied by the risk of flooding, as forecasters predict a combination of heavy rainfall and rapid snowmelt. The West Coast, the South, and the Ohio Valley/Appalachian regions are identified by Jason Elliott, the service coordination hydrologist at the National Water Center, as the three areas most susceptible to flooding.

On the West Coast, a moisture plume moving over northern California poses a threat, resulting in heavy rain that could lead to localized flash flooding, especially in urban areas, roads, small streams, narrow canyons/gullies, and areas affected by recent wildfires. The Pacific Northwest is also at risk due to warm rain on existing snow and ice.

AccuWeather forecasters warn of potential flooding in the South, emphasizing that areas from central and eastern Texas to western Tennessee may receive 4-6 inches of rain, with localized amounts up to 8 inches. This amount of rainfall could induce urban and flash flooding, even in drought-affected regions, and significantly elevate secondary river levels.

Aside from flooding concerns, the warmer temperatures in the South will lead to the melting of remaining snowpack in southern regions, accompanied by a shift to more humid air. This interaction may result in fog and low clouds across the Midwest, South, and East, according to Weather.com meteorologist Jonathan Erdman.

In the wake of severe winter storms in the USA, more than 90 weather-related deaths have been recorded, with Tennessee and Oregon remaining under a state of emergency due to severe ice storms. Power outages affecting 45,000 people were reported in Oregon, as well as in Pennsylvania, California, New Mexico, and Indiana. Icy conditions are expected to ease off in the next few days, although the US National Weather Service has issued an ice storm warning for parts of Arkansas and Oklahoma today.